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* doc/lispref/display.texi (SVG Images): Document svg-remove. * doc/lispref/display.texi (SVG Images): Document svg-text. * lisp/svg.el (svg-remove): New function. (svg-text): New function.
274 lines
7.6 KiB
EmacsLisp
274 lines
7.6 KiB
EmacsLisp
;;; svg.el --- SVG image creation functions -*- lexical-binding: t -*-
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;; Copyright (C) 2016 Free Software Foundation, Inc.
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;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
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;; Keywords: image
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
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;;; Commentary:
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;;; Code:
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(require 'cl-lib)
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(require 'xml)
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(require 'dom)
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(require 'subr-x)
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(defun svg-create (width height &rest args)
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"Create a new, empty SVG image with dimensions WIDTHxHEIGHT.
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ARGS can be used to provide `stroke' and `stroke-width' parameters to
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any further elements added."
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(dom-node 'svg
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`((width . ,width)
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(height . ,height)
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(version . "1.1")
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(xmlns . "http://www.w3.org/2000/svg")
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,@(svg--arguments nil args))))
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(defun svg-gradient (svg id type stops)
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"Add a gradient with ID to SVG.
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TYPE is `linear' or `radial'. STOPS is a list of percentage/color
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pairs."
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(svg--def
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svg
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(apply
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'dom-node
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(if (eq type 'linear)
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'linearGradient
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'radialGradient)
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`((id . ,id)
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(x1 . 0)
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(x2 . 0)
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(y1 . 0)
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(y2 . 1))
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(mapcar
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(lambda (stop)
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(dom-node 'stop `((offset . ,(format "%s%%" (car stop)))
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(stop-color . ,(cdr stop)))))
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stops))))
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(defun svg-rectangle (svg x y width height &rest args)
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"Create a rectangle on SVG, starting at position X/Y, of WIDTH/HEIGHT.
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ARGS is a plist of modifiers. Possible values are
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:stroke-width PIXELS. The line width.
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:stroke-color COLOR. The line color.
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:gradient ID. The gradient ID to use."
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(svg--append
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svg
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(dom-node 'rect
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`((width . ,width)
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(height . ,height)
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(x . ,x)
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(y . ,y)
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,@(svg--arguments svg args)))))
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(defun svg-circle (svg x y radius &rest args)
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"Create a circle of RADIUS on SVG.
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X/Y denote the center of the circle."
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(svg--append
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svg
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(dom-node 'circle
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`((cx . ,x)
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(cy . ,y)
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(r . ,radius)
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,@(svg--arguments svg args)))))
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(defun svg-ellipse (svg x y x-radius y-radius &rest args)
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"Create an ellipse of X-RADIUS/Y-RADIUS on SVG.
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X/Y denote the center of the ellipse."
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(svg--append
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svg
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(dom-node 'ellipse
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`((cx . ,x)
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(cy . ,y)
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(rx . ,x-radius)
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(ry . ,y-radius)
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,@(svg--arguments svg args)))))
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(defun svg-line (svg x1 y1 x2 y2 &rest args)
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"Create a line of starting in X1/Y1, ending at X2/Y2 in SVG."
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(svg--append
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svg
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(dom-node 'line
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`((x1 . ,x1)
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(x2 . ,y1)
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(y1 . ,x2)
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(y2 . ,y2)
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,@(svg--arguments svg args)))))
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(defun svg-polyline (svg points &rest args)
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"Create a polyline going through POINTS on SVG.
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POINTS is a list of x/y pairs."
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(svg--append
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svg
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(dom-node
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'polyline
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`((points . ,(mapconcat (lambda (pair)
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(format "%s %s" (car pair) (cdr pair)))
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points
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", "))
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,@(svg--arguments svg args)))))
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(defun svg-polygon (svg points &rest args)
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"Create a polygon going through POINTS on SVG.
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POINTS is a list of x/y pairs."
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(svg--append
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svg
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(dom-node
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'polygon
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`((points . ,(mapconcat (lambda (pair)
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(format "%s %s" (car pair) (cdr pair)))
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points
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", "))
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,@(svg--arguments svg args)))))
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(defun svg-embed (svg image image-type datap &rest args)
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"Insert IMAGE into the SVG structure.
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IMAGE should be a file name if DATAP is nil, and a binary string
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otherwise. IMAGE-TYPE should be a MIME image type, like
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\"image/jpeg\" or the like."
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(svg--append
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svg
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(dom-node
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'image
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`((xlink:href . ,(svg--image-data image image-type datap))
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,@(svg--arguments svg args)))))
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(defun svg-text (svg text &rest args)
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"Add TEXT to SVG."
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(svg--append
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svg
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(dom-node
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'text
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`(,@(svg--arguments svg args))
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text)))
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(defun svg--append (svg node)
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(let ((old (and (dom-attr node 'id)
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(dom-by-id svg
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(concat "\\`" (regexp-quote (dom-attr node 'id))
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"\\'")))))
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(if old
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(setcdr (car old) (cdr node))
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(dom-append-child svg node)))
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(svg-possibly-update-image svg))
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(defun svg--image-data (image image-type datap)
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(with-temp-buffer
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(set-buffer-multibyte nil)
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(if datap
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(insert image)
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(insert-file-contents image))
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(base64-encode-region (point-min) (point-max) t)
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(goto-char (point-min))
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(insert "data:" image-type ";base64,")
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(buffer-string)))
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(defun svg--arguments (svg args)
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(let ((stroke-width (or (plist-get args :stroke-width)
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(dom-attr svg 'stroke-width)))
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(stroke-color (or (plist-get args :stroke-color)
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(dom-attr svg 'stroke-color)))
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(fill-color (plist-get args :fill-color))
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attr)
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(when stroke-width
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(push (cons 'stroke-width stroke-width) attr))
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(when stroke-color
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(push (cons 'stroke stroke-color) attr))
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(when fill-color
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(push (cons 'fill fill-color) attr))
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(when (plist-get args :gradient)
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(setq attr
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(append
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;; We need a way to specify the gradient direction here...
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`((x1 . 0)
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(x2 . 0)
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(y1 . 0)
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(y2 . 1)
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(fill . ,(format "url(#%s)"
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(plist-get args :gradient))))
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attr)))
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(cl-loop for (key value) on args by #'cddr
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unless (memq key '(:stroke-color :stroke-width :gradient
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:fill-color))
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;; Drop the leading colon.
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do (push (cons (intern (substring (symbol-name key) 1) obarray)
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value)
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attr))
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attr))
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(defun svg--def (svg def)
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(dom-append-child
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(or (dom-by-tag svg 'defs)
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(let ((node (dom-node 'defs)))
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(dom-add-child-before svg node)
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node))
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def)
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svg)
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(defun svg-image (svg)
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"Return an image object from SVG."
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(create-image
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(with-temp-buffer
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(svg-print svg)
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(buffer-string))
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'svg t))
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(defun svg-insert-image (svg)
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"Insert SVG as an image at point.
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If the SVG is later changed, the image will also be updated."
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(let ((image (svg-image svg))
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(marker (point-marker)))
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(insert-image image)
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(dom-set-attribute svg :image marker)))
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(defun svg-possibly-update-image (svg)
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(let ((marker (dom-attr svg :image)))
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(when (and marker
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(buffer-live-p (marker-buffer marker)))
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(with-current-buffer (marker-buffer marker)
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(put-text-property marker (1+ marker) 'display (svg-image svg))))))
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(defun svg-print (dom)
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"Convert DOM into a string containing the xml representation."
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(if (stringp dom)
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(insert dom)
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(insert (format "<%s" (car dom)))
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(dolist (attr (nth 1 dom))
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;; Ignore attributes that start with a colon.
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(unless (= (aref (format "%s" (car attr)) 0) ?:)
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(insert (format " %s=\"%s\"" (car attr) (cdr attr)))))
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(insert ">")
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(dolist (elem (nthcdr 2 dom))
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(insert " ")
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(svg-print elem))
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(insert (format "</%s>" (car dom)))))
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(defun svg-remove (svg id)
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"Remove the element identified by ID from SVG."
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(when-let ((node (car (dom-by-id
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svg
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(concat "\\`" (regexp-quote id)
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"\\'")))))
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(dom-remove-node svg node)))
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(provide 'svg)
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;;; svg.el ends here
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